WASHINGTON (AP) -- About 162,000 trailer hitches sold at U-Haul outlets are being recalled because of weak steel that could cause the parts to break. The recall, announced Saturday, covers two types of hitches made by Wisconsin-based Curt Manufacturing between July 2014 and January 2015 and sold under the "U-Haul Power Tow" brand. They were sold only at U-Haul stores and online. Curt Manufacturing said a Chinese company, Shandong Jiyang Machinery, changed the way it cleaned steel during the hot-rolling process, reducing the steel's strength. The National Highway Traffic Safety Administration said that if owners don't also attach safety chains for the trailers, the defective hitches could mean a trailer breaking away from the vehicle towing it. The TS1 and TS2 hitches are rated to tow trailers weighing up to 7,500 pounds, but can break near the maximum load, according to a recall report posted on the highway agency's website. The agency said no injuries or property damage has been reported to the manufacturer. Curt Manufacturing will notify owners and replace the parts free of charge, according to the highway agency.